ROHM BA6402F Datasheet

Motor driver ICs

2-phase half-wave motor predriver

BA6402F

The BA6402F is a 2-phase, half-wave motor predriver suitable for fan motors.
Features

1) Lock detection and rotational speed sensing mecha­nisms are built in.

2) Hall constant current source is built in.

Block diagram and application example

3) Compact 8-pin SOP package reduces the number of
external components required.

Absolute maximum ratings (Ta = 25C)

Recommended operating conditions

689

Motor driver ICs BA6402F

FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 12V)

FRotational speed sensing and lock detection (6 pin)

The circuit around pin 6 is described in Fig. 1. Normally,
the C

6 external capacitor is charging or discharging

around the Hall signal when the motor is running. When
the motor is locked, discharging does not occur at C
cause the Hall signal stops switching. Charging contin­ues at C
voltage, and then Q
With the pin-6 current being constant (I

6 until the voltage increases to the pin-6 clamp

1 turns ON to turn OFF the output.

6=6.8µA, typical),

the time required after the motor is locked until the output
current is turned OFF (duration between B and C in Fig.

2) is determined by the C

Toff=TBC=

6 capacitance.

6CLVBEQ3) C6

(V

I6

4V

BE S C6

6.8µA (Typ.)

6 be-

4.12105C6 (sec) (Typ.)

where V
For C

6CL is pin-6 clamp voltage (nearly equal to 5VBE)

6=2.2µF, for example, Toff is about 0.91s (typical).

FOperation notes
(1) Hall constant current source (3 pin, 6.8mA typical­ly), which is directly connected with the IC bias circuit, is
not available when pin 3 is OPEN (saturated).
(2) Power dissipation
The allowable power dissipation is plotted against ambi­ent temperature in Fig. 3.

690

FThermal derating curve